Electric switch



Feb. 6, 1962 J. H. WILLIAMS ELECTRIC SWITCH Filed April 27, 1959 NW" af 077ML INVENTOR.

n aligned in lthe stack one above the other.

United States Patent C 3,020,375 ELECTRIC SWITCH John H. Williams, Barrington, Ill., assignor to Oak Manufacturing Co., a corporation of Delaware Filed Apr. 27, 1959, Ser. No. 809,121 2 Claims. (Cl. 200--166) This invention relates to an electric switch and more particularly to a switch construction where a large number of circuits carrying little power can be controlled.

yin such devices as electric organs, electric pianos and computers, it is -frequently necessary to provide a large number of key-controlled switches which can open or Close a multiplicity of circuits. As a rule, such switches carry very little power, operate at relatively low voltages but must be provided in large numbers in a small volume.

This invention provides a simple yand compact switch construction which is economical and effective.

in order that the invention may be understood, it will now be disclosed in connection with the drawings wherein FIGURE 1 is a plan `view with certain parts broken away of a switch construction embodying the present invention.

FGURE Z is a transverse section on line 2-2 of FIG- URE l. f

FIGURE 3 is a section on broken line 3--3 of FIG- URE l. i

The switch construction embodying the present invention includes a number of elongated strips yof insulating material. i the number of poles, and for illustration,the construction shown has four strips of insulation'ltl to 13` inclusive. Strips to 13 inclusive are preferably of rigid l material and may be of plastic, wood or Lthe like. The strips are rectangular, as seen in FIGURE l, and are adapted to be bolted together to form a stack. Between adjacent insulating strips are spacer strips to 17 inclusive. Spacer strips 15 to 17 inclusive are also of insulating material and are of the same size as stripsflt) to 13 inclusive.

Strips 10 to 13 inclusive have portions 10a to 13a inclusive which for convenience may be considered as forming the front portion of the stack.

The entire stack has front face and top face 21. inwardly disposed from front face 2) of the stack and extending generally parallel to the front face are shallow grooves or slots 22 to 27 inclusive in the various insulating strips. For example, insulating strip 10 has groove 22 in the top face thereof inwardly disposed from the front edge a short distance and extending lengthwise of the stack. Similarly, insulating `strip 11 has slots 23 and 24 on opposite faces thereof adjacent the -front edge. In? sulating strip 12 has slots 25 and 26 while insulating strip 13 has slot 27. v

FIGURE 2 shows that all these slots or grooves are Disposed in each slot is wire 30.

Each slot contains its own wire of brass, silver or other suitable metal which can stand up in use, Each wire 30 has one end shaped to form terminal loop 31 adjacent a stack end. Wire 30 is locked longitudinally in position in strip l0 by passing the same through spaced apertures 10b and 10c in strip 10. lt will be noted that for strip 10, wire 30 is looped upwardly'. In the remaining strips, the wire loops are alternated from one end of the stack to the other and are looped above and below the strips as shown in FIGURE 3. Wire 30 has end 32 short of the region where other wires are looped. Thus, the arrangement provides minimum interference between various wires 3l) so that one wire 30 may be electrically isolated from others.

Locked in the stack at various positions along the stack The number of such strips will depend upon u 3,020,375 Patented Feb. 6, 1962 ICC length are a number of transversely disposed contact leaves. Inasrnuch as these are generally similar, only one group of contact leaves has been illustrated ink section in lFIGURE 2 and two separate groups have been illustrated in FIGURE l. vAs many contact leaves may be provided in a group as may be desired, this depending upon the number of insulating strips to a stack and as many groups of contactleaves may be provided, this depending upon the length of the stack.

As an example, contact leaves 35, 36 and 37 are dis posed in the stack as illustrated in FIGURE 2.y Contact leaf has anchor portion 35a disposed between insulating strip 11 and spacer strip 15. Contact leaf 35 has terminal portion 35b extending rearwardly from a stack for connection to an outside circuit.

Contact leaf 35 extends from the rear part of spacer strip 15 andk lies in a region defined by slots 40 in spacer strip 15 and insulating strip 11. It is understood that slots are cut in both the spacer and insulating strips. In this instance, spacer strip 15 and insulating strip 11 are provided with slots 40. Within this slotted region, contact leaf 35 has spring portion 35e bent in a suitable shape, as illustrated in FIGURE 2, and extends forwardly of the stack to provide handle portion 35e.

It will be noted that contact leaf 35 has portion 35d which extends directly across and adjacent to a wire in slot or groove 23. As illustrated here, contact yleaf 35 is biased upwardly so that the exposed wire lying in slot 23 will be contacted by that particular leaf. It is possible to press handle portion 35e downwardly so that the leaf portion 35d will make contact with the wire in slot 252..`

Contact leaves 36 and 37 `are similarly constructed. Contact leaves 35 and 37 inclusive are in vertical registration when looking down `up the sameffrom theto'p so that slots 40 in strips 16, 12, 17 and 13 will all register. It is clear that the contact leaves 36 and 37 can be moved up or down with leaf 35 to engage certain wires in one position and other wires in another position. The various contact leaves 35 to 37 inclusive may be joined by suitable means and actuated by knob 40a. `-If desired, a blank insulating cover strip may be disposed over top face 21 to cover the slots and prevent the entry of dirt. The terminal portions of the contact leaves may be connected to'outside circuits.

The entire stack is maintained in position by rivets 42 or any other suitable means disposed at spaced intervals along the stack length in registering apertures 43; 44; etc.

' Apertures 44 are elongated along the stack length to allow for variations in dimensions of insulation. It is clear that where desired, the number of leaves in a switch group may be decreased. Thus, as shown in FIGURE 2, a group of switch leaves consists of leaves 35 to 37 inclusive. Another group might not require three leaves and instead may require only one or two. It is obvious that by building up the stack, any number of leaves per switch group may be provided. The various leaves will be connected to suitable circuits.

By virtue of the arrangement provided herein, expansion and contraction of wires 30 with reference to the insulating material will not result in any change in the switch action. The wires are preferably loose enough in each slot or groove so that a wire may contract or expand with temperature. However, the retention is preferf ably sutliciently tight so that when a contact leaf is pressed downwardly to engage one or more wires, there will be a minimum tendency to bend the wire.

Assembly of this switch is quite simple and the parts required are reduced to a minimum. If desired bolts or rivets may be provided for the front part of the stack between some switch groups. However, itis preferred not to grip wires 30 too tightly in the stack so that the wires may remain straight at the slotted regions.

What is claimed is:

l. An electric switch construction adapted to provide a large number of separate switches in an aligned' arrangement as for piano key arrangement, said construction comprising a stack having top and front faces extending along the stack length, said stack having its depth extending from the front face toward the rear face and the height of the stack extending from the top face to the bottom face thereof, said stack having a length great in comparison to depth or height, said stack consisting of clamped itat strips of insulation extending lengthwise and parallel to the top and bottom stack faces, said strips being disposed to form a laminated stack construction, said stack as a Whole having slots extending from the front face rearwardly for part of the depth of the stack, said slots being disposed in spaced parallel relation along the stack length, alternate strips having grooves in the surface thereof, each groove extending along the fuil length of a strip parallel to but oiset from the strip edge which forms part of the front face of the stack, all the grooves being in vertical alinement as viewed from the end of the stack, said grooves being interrupted at spaced intervals along the stack length where they intersect said slots, a contact wire for each said alternate strips, each contact Wire extending lengthwise of the stack and being substantially accommodated by the grooving to be tightly clamped between adjacent strips when said strips are tightly bound to form a compact stack, each of said alternate grooved strips having itsl own wire attached thereto adjacent one wire end with the other wire end being straight and stopping short of the strip end, the one end of said wire having a terminal portion extending beyond the strip end, said stack having such wire equipped strips so arranged that at each end of the stack, terminal portions alternate with blind dead wire ends, said wires #i being accessible at said slots, at least one liat movable spring metal contact strip for each slot, each contact strip extending transversely of the stack along a line extending from the back to t'ne front faces of the stack, each contact strip having a flat thin portion tightly gripped between strip faces at the rear parts of the stack, the contact strip extending forwardly along a slot toward and beyond the front face of the stack to provide a free portion of the contact strip for movement in a direction generally parallel to the stack height, each contact strip being movable in the stack slot toward or away from a contact wire, each contact strip having a terminal portion extending beyond the rear face of the stack so that separate contact strips can be in separate circuits with a contact Wire providing a common circuit connection and means for maintaining said strips tightly to provide a unitary stack.

2. The construction according to claim l wherein each of said at movable contact strips is bent whe e it emerges into the slot, each such Contact strip being bent out of its norrnal at condition to provide a spring arch for biasing the portion of the Contact strip which cooperates with the contact wire.

References Cited in the iile of this patent UNITED STATES PATENTS 1,179,389 Austin Apr. 18, 1916 1,528,761 Gott` Mar. 10, 1925 2,573,895 Eve-tt Nov. 6, 1951 2,562,091 Harrison July 24, 1951 2,741,670 Kent et al Apr. 10, 1956 2,785,238 Bissonette et al Mar. l2, 1957 2,931,877 Henley Apr. 5, 1960 FOREIGN' PATENTS 450,320 Great Britain July l5, 1936 526,371 Belgiun'l Feb. 27, 1954l 770,030 Great Britain Mar. 13, 1957 

